Returns the current time as a UNIX timestamp, referenced either to your server’s
local time or any PHP supported timezone, based on the “time reference” setting
in your config file. If you do not intend to set your master time reference to
any other PHP supported timezone (which you’ll typically do if you run a site
that lets each user set their own timezone settings) there is no benefit to using
this function over PHP’s time() function.

echonow('Australia/Victoria');

If a timezone is not provided, it will return time() based on the
time_reference setting.

The opposite of the unix_to_time() function. Takes a “human”
time as input and returns it as a UNIX timestamp. This is useful if you
accept “human” formatted dates submitted via a form. Returns boolean FALSE
date string passed to it is not formatted as indicated above.

The first parameter must contain a UNIX timestamp.
The second parameter must contain a timestamp that is greater that the
first timestamp.
The thirdparameter is optional and limits the number of time units to display.

If the second parameter empty, the current time will be used.

The most common purpose for this function is to show how much time has
elapsed from some point in time in the past to now.